The present invention relates, in general, to lock or sealing rings for mounting watthour meters on meter enclosures and, more particularly, to lock or sealing rings using barrel locks.
In the electric utility industry, watthour meters are employed to measure electrical power consumption at a residential or commercial building establishment. A cabinet is typically mounted on an outside wall of the residence or building and contains a meter socket having pairs of line and load contacts which are connected to electric power line conductors extending from the utility power network and electric load conductors connected to the residential or building establishment power distribution network. The contacts receive blade terminals on a plug-in watthour meter to complete an electric circuit through the meter between the line and load terminals mounted in the cabinet for the measurement of electrical power consumption.
Lock rings are commonly employed with ring-style sockets which have a circular flange projecting from the major plane of the socket cover for coupling a mating flange on a watthour meter to the socket cover to attach the watthour meter to the socket in a position where the blade terminals of the watthour meter are securely engaged with the electrical jaw contacts in the socket.
Watthour meter socket adapters which provide an extension between the blade terminals carried by the socket adapter and the socket jaw contacts to jaw contacts carried by the socket adapter which engage the meter blade terminals are also affixed to ring style meter socket covers by the same lock rings. When a socket adapter is used, a second lock ring is employed to mount the watthour meter to the outer end of the socket adapter.
The lock rings typically include an annular wall with radially inward extending side walls. The annular wall terminates in two spaced ends which may have perpendicularly extending flanges extending from each end, each with an aperture formed therein, extending from each end. The apertures for alignment to receive a seal or lock member to securely affix the lock ring to the meter/socket adapter/meter socket cover flanges and at the same time prevent easy removal or at a minimum provide evidence of tampering with the lock ring in an attempt to obtain non-metered power from the meter socket.
Plastic or wire seals have been employed to secure the ends of the lock ring together. However, such seals are easily cut. Barrel locks having a key operation provide greater security. In addition, when a barrel lock is employed on a lock ring, the lock ring is typically formed of a heavier gauge material to make it more difficult to cut the lock ring in an attempt to remove it from the meter socket/watthour meter flanges.
However, the heavier metal used in lock rings with barrel locks is more difficult to bend into a circular form. In addition, bending the perpendicular end flanges requires a second machine operation. Both factors contribute to a higher lock ring manufacturing cost.
To make it easier to bend the heavier gage material, scallops or cutouts are formed in at least one of the radially inward extending sidewalls of the lock ring LR, shown in FIG. 11. However, the scallops provide a surface which can be forced into engagement with the socket or meter mounting flange and act as a thread which can enable the lock ring to be twisted off of the mating flanges to enable removal of the meter and access to the interior of the meter socket.
In addition, lock rings are used with meter socket cover rings and watthour meter/socket adapter mounting flanges which can, according to industry standards, vary up to 0.280 inches in circumference. As a result, lock rings are typically manufactured to the largest standard circumference of the meter socket mounting ring. However, when such lock rings are used with meter sockets, watthour meters or watthour meter socket adapters in which the mounting rings have a smaller circumference, the lock rings, even when locked, sloppily fit around the mounting flanges thereby increasing the opportunity for tampering.
In many prior art lock ring configurations, particularly those using a “barrel lock”, a portion or all of the barrel lock itself is exposed to view when in the locked position. This provides an opportunity to tamper with the barrel lock in an effort to loosen or remove the sealing ring from the meter socket and obtain access to the interior of the socket.
One Prior Art attempt to address these security issues is shown in FIG. 11. In this lock ring LR, a lock pin LP with retractable and extendable locking balls LB are inserted through lined apertures on end flanges extending perpendicularly from opposed ends of the lock ring LR. The shank of the lock pin LP carrying the locking balls LB is inserted into a lock cap LC. The locking balls LB selectively engage one of a plurality of spaced grooves G formed interiorly within the lock cap LC to secure the lock ring LR tightly about the mounting flanges of a watthour meter, meter socket adapter or meter socket cover. However, this prior art lock ring still has several deficiencies. For one, the entire lock ring is exposed to view thereby enabling easy attempts to tamper with the lock ring or lock pin. Secondly, use of this lock pin LP and lock cap LC is difficult since the installer must hold the ends of the lock ring LR tightly about the mating mounting flanges, insert the lock pin LP through the aligned apertures in the ends of the lock ring LR while holding the lock cap LC in a position to receive the shank and lock balls LB of the lock pin LP. This assembly process is awkward at best.
Thus, it would be desirable to provide a lock ring for a watthour meter enclosure which can be made at a lower manufacturing cost, with fewer machine operations, and which provides a high level of security to thwart tampering attempts.